Though I'm an active member of several forums, I've not run one myself. It seems the popular forum scripts are vbulletin and phpbb. Vbulletin cost $$ while PhpBB is free. Anyone care to share why?
phpBB is a project run by volunteers, so they just do what they want. If you have a problem and need help the most you can do is post on their forums and wait a couple days for a reply. Whilst vB is run by paid people, you'll get many more features and there's a support hotline for immediate help.
There are a lot of vBulletin that can't be found on phpBB, especially the add-on functionalities. If you want FREE, I suggest MyBB. It still on their young age of development but the features are great. http://www.mybboard.com
Well, vBulletin provides phone and email support. Since you pay for the license, you receive more attention. I have heard that the backend of vBulletin is extremely well written. If using for a very large site, I would use vBulletin. If using for a smaller personal site you can test out many of them at opensourcecms.com Good Luck!!
main difference is the backend - i.e. the control panel features that the admin uses/sees. if you're in for the long term, i strongly suggest going for vbulletin.
Seems that you don't care with the cost. So I highly suggest vBulletin. vBulletin Admin Panel seems difficult at first glance but as times goes by you can see how powerful it is. Another thing about vBulletin is that it can be made as a CMS - that's how flexible vBulletin is. I often heard of a phpBB forum hacked but never on vBulletin. Security issuess is another concern.
Yes, cost is not a problem if the product can give me what I want. The problem I find with many open source scripts are that they are somehow not quite right. For example, they may have too many unwanted features. Another may not be user friendly enough, or it's difficult to install. Either this or that... Flexibility and customizability are two great great pluses for me.
I recently switched from phpbb to vb, I get to spend more time participating in my forums than moderating the forums now. I mean, its so easy to move/delete posts with vb...The backend makes all the difference IMO. vb seems to work really well for my boards and for me, it saves me the update time...(i might be lazy...but i've got other parts of the site to look after as well..). Switching to vb is a decision I'll never regret so yeah, if you want your forum to be big...go for it